Control apparatus



E. D. RANEY 2,337,925

CONTROL APPARATUS Filed Oct. 21, 1939 4 Sheets-Sheet l- Dec. 28 1943' III HH INVEN p n 37 Q Dec; 28, i943. E D RANEY 2,337,926

CONTROL APPARATUS Filed Oct. 21, 1959 4 Sheets-Sheet 2 'INVENTOR EWWQZWA AT-TO-RNEY g Dec. 28, 1943. E RAQEY' 2,337,926

CONTROL APPARATUS Filed Oct. 21, 1939 4 Sheets-Sheet 3 1 30 INVENTOR E/dam 4 BY WM ATTORNEY IIIII E. D. RANEY' Dec. 28, I943.

CONTROL APPARATUS 4 SheetsSheet 4 Filed Oct. 21, 1959 {INVENTOR M P BY on f f ATTORNEY Patented Dec. 28, 1943 CONTROL APPARATUS Eldon D. Raney, Columbus, Ohio, assignor to Ranco Incorporated, Columbus, Ohio, a corporation of Ohio Application October 21, 1939, sci-mm. 300,611

4 Claims.

and having an actuating member for moving the control member to the other of the positions and a thermostatically controlled element for resisting the movement of the control member in the direction of its bias independently of the actuating member.

It is a further object of the invention to provide a control apparatus as described in the preceding paragraph in which the actuating member and the resisting element may move each in one direction without aflecting the control member, for permitting the control of the'control member to be shifted from the actuating member to the resisting element and vice versa.

Other and further objects and advantages will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a side view of V a control apparatus with the casing cover removed, part of the apparatus being shown broken away;

Fig. 2 is a view of the control apparatus taken from the side opposite that shown in Fig. 1, part of the casing being shown broken away;

Fig. 3 is an end view of the control apparatus;

Fig. 4 is a side view of certain members of the control actuating mechanism and resisting mechanism;

Fig. 5 is an end view of the mechanism shown inns-4:

Fig. 6 is an enlarged fragmentary view partly in section, showing the snap switch and part of the actuating mechanism therefor:

Fig. 'l is an enlarged top view of a toggle switch, part thereof being broken away;

Fig. Bis a perspective view of a switch lever;

Fig. 9 is a perspective view of a flipper lever:

Fig. 10 is a sectional view taken on line lO-ifl of Fig. 1;

Fig. 11 is a diagrammatic illustration of a control apparatus and a refrigerating system controlled by the apparatus;

Fig. 12 isa diagrammatic illustration of the control apparatus showing the resisting element operative to maintain the control member in a position intermediate two control positions and the actuating member withdrawn from the control member, and

Fig. 13 is a view similar to Fig. 8 but showing the control member in one extreme control position.

Referring to the drawings a control apparatus 20 is shown that is adapted to control the operation of an electric refrigerating system. The control apparatus includes a casing 2i, formed with a top wall 22, a side wall 23, a bottom wall, and an end wall 25. Preferably, the remaining open end and side are closed by a suitable cover, not shown. g

A switch base 26, formed of insulating material such as Bakelite, is mounted between the top and bottom walls of the casing. The top end of the base 28 is secured in place by a screw 2'! and the lower end of the base is riveted to the yoke of a. fixed bracket H by rivets 28. The bracket Ii is secured to the bottom wall it by screws 69. A lug 28 is formed on the side of the base 26 and fits into an opening 30 formed in the side all 23 to further stabilize the base. A pair of contacts 32 are secured to the base 26 and each contact is connected to a terminal 33 disposed on the opposite side of the base. Line wires for a refrigerator motor circuit may be brought into the casing through a shielded opening indicated at 3%.

A snap switch 35 is mounted on the base 26. The switch comprises a bracket 36, a contact carrying switch lever 31 pivotally supported on the bracket, 9. flipper lever 36 pivotally supported at one end on one endof the lever 31 and con-- nected at the other end to the lever N by a lost motion connection, and a tension spring as connecting the flipper lever 38 and a control lever 59. The bracket 86 is U shaped, and the yoke thereof is riveted to the base 26. V notches in are formed in the lower edge of the two legs of the bracket for receiving pivot lugs formed on the switch lever 31. The switch lever 81 is formed by a channel shaped member 4! and a fiber member 42 that is Joined to the member 4|. The member ti is disposed between the less of the bracket 36 and is formed with flanges 48 at one end that extend from either side thereof. The fiber member 42 is U shaped and cars it formed on the flanges 43 are folded over the edges of the legs of member 62 and firmly secure the fiber member to the member ll. A contact bar 45 is attached to the end of the fiber member. Contacts 46 are riveted on either end of the bar 45 and are adapted to engage the fixed contacts 82. Edges or the flanges 43 form shoulders 41 which engage in the vertex of thenotches 48 to form pivots for the switch lever 31. The edges of the shoulders 41 are'beveled to form knife'edge bearings. The yoke of the channel shaped member 4| is formed with a conical section 48 at one end to allow space for the tension spring 38. A shoulder 48 is formed on each side of the member M at the upper end thereof and edges of these shoulders serve as pivots for the flipper lever 38. The edges of the shoulders 49 are beveled to present knife edge bearin points. The flipper lever 38 is formed of a flat strip having a pair of flanges 8| formed at one end and one on either side thereof. These flanges are spaced to fit between the outer walls of the channel shaped member M and the legs of the bracket 38. V notches 82 are formed in one edge of each flange 8| and receive the edges of the bearing shoulder 40. A flange 88 is formed at the opposite end of the strip and a fiber fork member 84 is riveted thereto. The fork member 84 is formed with two fingers 88 and 88 that straddle the yoke of the fiber member 42. The spring 38 is connected at one end in an eyelet 51 formed in the flange 53 and the other end is connected in an eyelet 58 formed in the control lever 59. The spring 39 biases the flipper lever 38 against 'the shoulders 48 and also biases the shoulders 41 of the lever 31 in the notches 40. When the control iever 88 is moved to the left, as viewed in Fig.- 112;; the center of the spring (represented in Figs-11, 12 and 13 by a dotted line) is moved to'the left of the pivot for the flipper lever 38. This snaps the flipper clockwise about its pivot causing the finger 58 to engage the switch lever 31 and rotate the switch lever to close the switch contacts. The switch closing movement of the switch lever moves the pivot of the flipper 38 well to the right of the center of the spring 38. When the control lever 58 moves the spring 88 to the right of the flipper lever pivot,

- the flipper is rotated counterclockwise about its forcefully open the switch should the contacts stick for any reason and prevent the snap mechanism from opening the switch. It is apparent that to open and ,close the switch, the control lever 59 must be moved between two extreme positions at which positions the switch is opened and closed with a snap movement. The control lever 59 is pivotally mounted on an actuating lever 85. The lever 85 is pivotally supported by a pin 88 iournaled between uprights of the bracket II and is formed with an upturned flange 88 on one side thereof and an upwardly extending arm 81 on the opposite side. The control lever 58 is supported on a pin I2 journaled at either end in the flange 88 and the arm 81. A coiled spring 13 is disposed around the pin 12, one end thereof engaging the control lever 88 and the other end the actuating lever 88. This spring continuously biases the control lever 88 in the switch opening direction.

The arm 81 of the actuating lever has an extending finger 18 that supports a screw 18-. The

- by the arm 81, but the arm .81 may be separated from the lever 59 during movement of the actuating lever 85 in the switch opening direction.

The actuating lever is moved in the switch closing direction by a thermostatic device 85.

The thermostatic device 85 comprises a cup-like casing 88, a bellows 81 and a tube 88 connected to the shell, the tube being provided with a bulb 89 at the end thereof. One end of the bellows is closed as at 88 and the edges 01 the opposite end are hermetically Joined with the walls of the shell. The bellows thus forms a flexible wall for the shell. The enclosed portion of the shell, tube and bulb are filled with a suitable temperature responsive fluid, such as for example, methyl chloride vapor, the pressure of which varies as the temperature varies. A pin 9I is connected to the end wall 80 of the bellows and the end thereof abuts a detent 92, formed in the actuating lever.

A threaded stud 98 extendsthrough the bottom wall of the casing 2I andthgough an opening in the end of the actuating lever 85.

The stud has" a tapered, squared head 91, two sides of which engage portions 98 of the bottom wall and are turned upwardly to form the opening for the stud. The portions 98 assist in preventing the head from being drawn through the bottom wall. The flat surfaces of the head 91 engaging the portions 98 prevent rotation of the stud. A compression spring I80 is disposed around the stud and the lower end thereof engages the actuating lever 65. A boss I8I,formed on the lever 65 centers the spring. A washer I02 forming a downwardly extending boss for centering the top of the spring I88 is disposed on the stud. The position of the washer I82 on the stud may be adjusted by an adjusting nut I03, threaded on the stud. The nut I83 is formed with a knurled flange I04 and a shoulder I85 that engages the washer I02. The nut I03 is locked in position by a lock nut M8. The upper end of the stud 96 is provided with a shank I01 that is journaled in an opening formed in a stud I I0, described hereinbelow.

The thermostatic device, and spring I08 coact to rotate the actuating lever 85 about its pivot. When the pressure within the casing 88 increases,

due to an increase in temperature of the fluid 25, limits counterclockwise rotation oi. the actuat- I ing lever. When the pressure in the casing 86 decreases due to a decrease in temperature of the fluid. in the bulb 89, the spring I00 may move the actuating lever clockwise as the pin 9I descends.

A channel shaped lever H2 is pivoted between two spaced ears I I3, struck downwardly from the top wall of the casing 2 I, by a pin I It. A depending arm H5 is formed on the lever H2 that is adapted to be engageable with, but unattached to, a laterally extending lug IIB secured to the control lever 59. A screw I I1 is threaded in one end of the lever I I2 and abuts the top wall 22 to provide a stop for the lever H2 when the lever is rotated clockwise, as viewed in Fig. 1. A look nut H8 is provided on the screw III to lock the latter in position. The lever II2 is adapted to be rotated clockwise by a thermostatic device I20 that is similar to the device 85. The device I20 comprises a casing I2I housing a bellows I22 that has the edges of one end hermetically joined with the walls of the casing and a closing end I23. A tube I24 is connected with the casing. The tube and casing contain a temperature responsive fluid such as methyl chloride vapor. The end of the tube I24 is closed and coiled to form a condenser. The bellows I22 is connected to the lever I I2 by a pin I25 that is attached to the end wall I23 of the bellows.

Thestud IIO extends downwardly through an opening in the top wall 22 into the casing 2|. A shoulder I23 formed on the end of the stud IIO supports the stud on'wall 22. A washer I21 is threaded on the stud I I having a depression I23 formed therein for seating a compression spring I28, which compression spring I28 is disposed around the stud between the washer I21 and the end of the lever I I2. A boss I34 is formed on the lever II2 for centering the spring. A pair of cars I30 are formed on the washer I21, which ears are disposed between the end wall 25 and flanges I3I formed on a T shaped strip I32 secured to the end wall 25. The ears cooperating with the wall 25 and the flange I3I prevent rotation of the washer and stabilizes the studs 96 and H0. A washer I33 is disposed on the shank I01 between the studs to limit downward movement of washer I21.

An adjusting knob I35 is secured on the end of the stud III! which knob is provided with a pointer I36. A pin I31 secured on the top wall in the path of the pointer I33 limits rotation of the knob I35. An indicia plate I38 is attached to the top wall 22 and cooperateswith the pointer I36 to indicate the temperatures at which the switch 35 is opened.

The control apparatus 20 is particularly useful in controlling air temperatures of a refrigerator cabinet. Referring to Fig. 11 the control apparatus 20 is shown controlling a refrigerating system I40.

The refrigerating system is a compressor-condenser-expander type and includes a compressor I4I, condenser receiver I42 and an evaporator I43, all suitably connected in a closed circuit as is well understood in the art. Theevaporator I43 is mounted in a refrigerator cabinet I44 and when the compressor is operating gaseous refrigerant is withdrawn from the evaporator through tube I45, compressed by the compressor, and directed through tube I48 into the condenser I42 where liquid refrigerant collects. The liquid refrigerant is then directed through a tube I41 to an expansion valve I48 and into the evaporator I43. The liquid refrigerant entering the evaporator I43 expands and absorbs heat as is well understood in the art. An electric motor I50 drives the compressor. The circuit for the motor includes line wires II and I52 and the switch 35 or the control apparatus 20 is connected in the line ISI to control the operation of the mo, tor. The bulb 89 is placed in direct heat transfer relation with the evaporator I43 and the coiled end of the tube I24 is placed in the air space or the cabinet I44. The refrigerating system illustrated may be for storing meats and the like in which it is desirable to maintain the air temperature at 38 deg. Rand to defrost the evaporator on each cycle of operation of the system.

Preferably the spring I00 and the stop screw 80 are adjusted so that when the temperature of the bulb reaches 34 deg. F. for example, the

pressure on the bellows 05 will cause the actuating lever 85, to move the control lever 58 to the switch closing position, and when the temperature of the bulb is reduced to 28 deg. F. for

example, the. spring I00 will overcome the pressure in the thermostatic device to move the actul ating lever to a position at which the control lever 58 will open the switch 35. It is to be understood that the control lever 59 is biased toward the switch opening position by the spring 13 at all times. Thus, if the lever H2 is not moved into the path of the control lever 59, the switch 35 will open when the temperature of the bulb 83 drops to 28 deg. F. The tension of the spring I28 is adjusted so that when the temperature of the coiled end of the tube I26 is above 38 deg. F., the pressure within the thermostatic device I20 will cause the lever II2 to be rotated clockwise to a position to prevent the controllever 53 from moving to the switch opening position. As the temperature of the. coil falls to.- ward 33 deg. E, the temperature desired to be maintained in the cabinet, the spring 28 will move the lever Il2 counterclockwise, due to the decreasing vapor pressure in the thermostatic device I20 and the'control lever 59 will follow the arm H5 or the lever. When the temperature of the air in the cabinet is reduced to 38 deg. F.-, the lever II2 will be moved to the position at which the lever 59 will open the switch. The elements will then be in the position shown in Fig. 13. It is to be noted, however, from the position of the elements shown in Fig. 12 that'if the temperature of the air has not been reduced to the desired minimum, the arm H5 ls'not retracted and, as shown by this figure, reduction of temperature in the evaporator below 28 deg. F. will have no effect to open the switch, because, under such condition, lever 59 will engage arm H5 and will be stopped thereby, while lever 85 will continue to rotate clockwise.

Thus, although the temperature of the evapator is reduced to below 28 deg. F. the cooling operation of the refrigerator will continue until the air has been reduced to the desired minimum temperature, 1. e. operation of the compressor will be stopped only after the evaporator and the air has been reduced to the desired minimum temperature. Since the arm H5 is limited in its clockwise movement and cannot move lever 33 far enough to close the switch, and since arm 81 is the only element for moving lever 53 far enough to close the switch, the cooling operation will be started only after the bellows 85 has expanded sufilciently to actuate the lever 53 to its switch closing position. Since the cooling op.- eration is started solely in response to the temperature of the evaporator, and since the temperature at which the starting can be adjusted, by controlling the tention of spring Hill, the switch can be adjusted so that it will not be closed until the temperature of the evaporator has been increased above the ice and frost melting temperature. In this manner the evaporator is cyclically defrosted.

It is to be noted that the stop screw ii? is ad- Justed so that the lever I I2 cannot move the control lever 58 to the switch closing position if the cabinet I 44 should warm above 38 deg. F. before the switch is closed by the actuating lever 85. It is to be understood, however, that the stop may be adjusted so that either of the levers IE2 or 88 could move the control lever 53 to the switch closed position. While the form of embodiment of the presen um therein and means for circulating refrigerant through the evaporator; a control mechanism for said means including a member for starting the circulating means when said member is moved to one position and for stopping the circulating means when said member is moved to a second position; a spring constantly biasing the member toward said second position;

a thermostatic device for moving said member to the first mentioned position, said device being ineffective for urging said member to said second position and being operable according to changes in temperature of the evaporator for operating said member; and a thermostatic device having a part thereof movable gradually according to gradual changes in temperature of said medium, said part being movable gradually into the path of movement of the movable member toward saidsecond position for yieldingly resisting movementoi the member to said second position.

2. In combination with a refrigerating system including an enclosure, an evaporator in the enclosure for aii'ecting the temperature of a medium therein and means for circulating refrigerant through the evaporator; a control mechanism for said meansfincluding a movable member for starting the circulating means through the evaporator when said member is moved to one position and for stopping the circulating means when said member is moved to a second position; a spring constantly biasing the member toward said second position; a thermostatic device operable according to changes in temperature of the evaporator for moving said member to the first mentioned position, said device being ineflective for urging said member to said second position; a thermostatic device having a part thereof movable gradually in accordance with gradual changes in temperature of said medium, said part being movable gradually into the path of movement of the movable member for yieldingly resisting movement oi the member to the second mentioned position, the second mentioned thermostatic device being operable according to changes in temperature of said medium; and means forming astop for preventing movement of said'member by the last mentioned thermostatic device to the first mentioned position.

,3. In a control apparatus, a control member movable between two extreme control positions; means for constantly biasing the control member toward one of the control positions; thermostatically controlled actuating means for moving the control member to the other of said control positions, said thermostatically controlled actuating means being inefiective for urging the control member to said one control position; an element independent of the thermostatically controlled actuating means for yieldingly resisting movement of the control member, by the first mentioned means, toward the said one position; thermostatic means for varying the yielding efiect of said element; and means forming a stop'ior preventing movement of the control member by the element to said other control position.

4..In a control apparatus, a control member movable between two extreme control positions; means for constantly biasing the control member toward one 01' the control positions; thermostatically controlled actuating means for moving the control member to the other of said control positions, said thermostatically controlled actuating means being ineffective for urging the control member to said one control position; an element independent of the thermostatically con- 1 trolled actuating means for yieldingly resisting ELDQN n. RANEY 

